Thanks. The photos on the website Sugarchile posted look like what's
on my tree.
If it looks like black knot prune it off immediately. Make your cut
at least 6 inches away from the knot. Use a sharp tool and be sure to
sterilize it after each cut so you do not spread the pathogen. I use
a 10% bleach solution for sterilization.

Remove and burn the cuttings.

I'll do that.

vince norris